The present invention relates to an apparatus for dispensing paper towels of a predetermined length from a supply roll of a continuous paper web.
There are known dispensers of the above type wherein, upon pressing a push button or a lever, a predetermined length of paper web is advanced outside the dispenser so that the user can detach a paper towel by hand, usually by tearing the protruding web length through a pull action against a saw-toothed blade.
The known dispensers have a number of drawbacks, the most relevant of which are the following. The length of the paper web dispensed each time is rigorously predetermined when designing the apparatus and cannot be altered, or only through replacement of a considerable portion of the dispensing mechanism. This is a disadvantage for the manufacturer forced to market more than one model of the same apparatus or to appreciably modify an existing model to meet the requirements of his customers. Moreover, where the dispensed paper length is either too long or too short, there will be a waste of paper since in the latter case the user will draw more than one towel from the apparatus.
A second drawback of prior art dispensers is that the user must positively detach the dispensed web, often causing the apparatus to jam. It is to be noted that the user's hands are wet when tearing the web preventing use of papers with lower tear strength. On the other hand papers formed of two thin sheets are highly desirable for their absorbency, softness and cost, but cannot withstand a pulling action with wet hands.
A prior art dispenser is described in U.S. Pat. No. 3,408,125 which provides for the manual extraction and cutting of a paper strip by the user, while the apparatus stores a fraction of the power received so that after a predetermined number of cycles, a length of paper to start a new cycle is caused to be fed outward.
U.S. Pat. No. 3,730,409 describes a dispenser apparatus in which cutting the paper web available at the outside is carried out manually by the user and causes the actuation of an electric motor that feeds a further paper length.
U.S. Pat. No. 4,131,044 describes a dispenser of the above-mentioned type, in which a predetermined paper length is drawn manually while some power is stored at the same time for the subsequent operation of a movable blade for cutting the paper web.
U.S. Pat. No. 4,697,146 describes a manually operated dispensing apparatus in which only a prefixed length of paper web can be drawn outside and torn by means of a timer preventing the paper web from unrolling. A fraction of the applied power is stored to cause a length of paper to be fed, after tearing, and to remain accessible from outside in order to start the subsequent cycle. The length of the dispensed strip can be previously selected among two or three values by acting onto the dispensing mechanism.
All these devices provide for a completely manual operation, except for the one described in U.S. Pat. No. 3,730,409 wherein only the feeding operation is motorized and the cut still must be carried out manually by the user. Therefore the above-mentioned drawbacks remain unsolved and even according to the last mentioned patent a certain length of paper is left exposed outside of the apparatus with further inconveniences of hygienic nature.